Expandable Spinous Process Fixation for Stable Fusion Support
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Solution Overview
Problem
Existing medical devices fail to provide effective structural stability and supplemental fusion for adjacent vertebrae to treat conditions such as degenerative disc disease, spondylolisthesis, trauma, and tumors, while minimizing damage to the spinous processes.
Innovation Solution
An implantable device with an expandable central barrel and lordotic plates, featuring projections that engage the spinous processes, allows for distraction and immobilization, and includes a mechanism to angulate and lock into position, providing support and fusion without excessive force on the spinous processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fusion devices are used to provide structural stability and supplemental fusion, then spinal conditions can be treated, but excessive force is applied to the spinous processes causing damage
Solution Approach 1:
The device divides the stabilization function into two separate components: the expandable cage handles compression and fusion support, while the distractor handles distraction and spinous process spacing. This segmentation allows each component to perform its specific function without subjecting the spinous processes to excessive combined forces.
Solution Approach 2:
The distractor acts as an intermediary mechanism between the implant and the spinous processes. It provides controlled distraction and spacing while the cage provides structural support, thereby mediating the forces applied to the spinous processes and preventing direct excessive loading.
2Reliability
If the spine is stabilized using rigid fusion devices, then structural support is provided, but normal physiologic motion is restricted
Solution Approach 1:
The device transitions from a static rigid fusion construct to a dynamic system where the expandable cage can be adjusted post-implantation. The cage expands from a compressed delivery state to a larger functional state, allowing adaptation to the patient's anatomy and motion requirements while providing structural support.
Solution Approach 2:
The device utilizes parameter changes in the form of expandability. The cage volume and compression force can be adjusted after implantation by inflating or expanding the cage structure, allowing optimization of both structural support and preservation of physiologic motion based on patient-specific needs.
3Reliability
If the expandable cage is inflated or expanded after implantation, then structural support is enhanced, but the delivery system becomes more complex
Solution Approach 1:
The expandable cage is nested within the delivery system during implantation. The compressed cage fits inside the delivery catheter or inserter, allowing minimally invasive placement. After positioning, the cage is expanded in situ, eliminating the need for complex external expansion mechanisms while maintaining the expandable functionality.
Solution Approach 2:
The cage structure is designed to be self-expanding or self-inflating after implantation. The expansion mechanism is integrated into the cage itself rather than requiring separate external actuation systems, simplifying the overall delivery system while maintaining the ability to enhance structural support post-implantation.
Data Source
AI summary
An implantable device may include a barrel, the barrel having an upper portion and a lower portion. The implantable device may further include an actuator assembly disposed in the barrel, and a central screw that extends from a rear ramped actuator through a front ramped actuator. The implantable device may further include a first plate having multiple projections extending from one side of the first plate. The implantable device may further include a second plate having multiple projections extending from one side of the second plate, the second plate configured to be received on the central screw. The barrel may be configured to transition from a collapsed form having a first height to an expanded form having a second height and wherein the second height is greater than the first height.